The historic significance of the Old Courthouse in St. The building of the Old Courthouse had gone through initial design and construction (circa 1816), redesigning and expansion (1839), had a new cast iron dome replacing the cupola (1861-1864), became a part of the Gateway Arch National Park (1940), and had several subsequent repairs and renovations during the following decades. The Old Courthouse is considered to be one of the oldest historic buildings in downtown St.
